GB2070993A

GB2070993A - Die finish-cutting machine

Info

Publication number: GB2070993A
Application number: GB8041381A
Authority: GB
Original assignee: Desousa M E X
Current assignee: Desousa M E X
Priority date: 1980-01-08
Filing date: 1980-12-29
Publication date: 1981-09-16
Also published as: PT72321B; GB2070993B; PT72321A; DE3100305A1; JPS56146617A; CA1141996A; US4322191A

Description

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GB2 070 993A 1

SPECIFICATION

Die finish-cutting machine

5 This invention relates to apparatus for cutting or finishing female dies used with male punches and in particular dies which have an opening through them which has an internal outline exactly matching the external outline 10 of the punch and receiving the punch to cut out a piece of metal or other sheet material with the outline of the punch and die. Before the opening through the female die precisely matches the punch the die opening is rough 1 5 cut to an outline smaller than that of the punch. Hitherto the die opening has then been hand filed from its rough form to the outline exactly matching the punch.

The need exists for cutting the outline of 20 the punch or other template on a die or similar workpiece by automatic or semi-auto-matic apparatus and a general object of the invention is to provide such apparatus.

In one aspect the invention provides an 25 apparatus for cutting a predetermined outline on a female die workpiece; said apparatus comprising a base, a first carriage mounted on the base, a second carriage movably mounted on the first carriage, cutting means supported 30 by the base for engagement with a workpiece mounted to the second carriage, a template mounted on the first carriage and defining said predetermined outline and a follower or finger mounted on the second carriage for 35 engaging and following the template to control the cutting means whereby during cutting thd follower and the cutting means are maintained in engagement with the template and the workpiece respectively.

. 40 In another aspect the invention provides an apparatus for cutting a predetermined outline on a workpiece; said apparatus comprising a base, a workpiece carriage and a template carriage movably mounted one upon the other 45 and upon the base, a workpiece holder on the workpiece carriage for holding the workpiece for movement with the workpiece carriage relative to the cutter, a template on the template carriage having the predetermined out-50 line, and s tracer on the workpiece carriage for following the template outline, the cutter and tracer respectively engaging the work-piece and template in the same direction so that reaction of the workpiece to cutting ac-55 tion urges the template and tracer into engagement.

The punch or template follower and the die cutter cooperate to maintain engagement between the follower and the punch or template 60 and between the cutter and the die. The punch can thus be used to locate the rough cut die.

The follower or tracer can be supported on a hinged mount able to swing the template 65 1 80° into opposition to the workpiece so that the die or workpiece can be adjusted until properly registered with the punch or template. The template and workpiece carriages preferably hold the template and workpiece at 70 different levels. The template carriage can then include a template holder pivotably mounted on the template carriage so that the template may be swung from the tracer to the level of the workpiece for axial alignment 75 therewith.

A linear drive can propel the workpiece carriage to cut along linear portions of the workpiece. A linear portion of the template would then simultaneously move along the ' 80 tracer to urge the template and both carriages in a second direction normal to the direction of movement of the workpiece carriage to the extent that the template deviates from linearity. Arcuate surfaces can be cut from the 85 workpiece off the rotational centre of the workpiece holder. To cut arcuate or curvilinear surfaces both the template and the workpiece can be rotatably mounted on their respective carriages and moved by a rotary drive. An 90 adjustable eccentric can be coupled between the rotary drive and the workpiece carriage to translate this carriage during rotation so as to compensate for displacement of the workpiece rotational axis from the axis of curvature of 95 the arcuate surface.

Apparatus constructed in accordance with the invention preferably also includes a template holder rotatably mounted on the template carriage, the workpiece holder securing 100 the workpiece for rotation about a first axis, a rotary drive coupling the template holder and workpiece holder for coordinated rotation of the template and workpiece while cutting an arcuate outline around a second axis, and an 105 eccentric coupled to said drive for moving the workpiece carriage to hold the second axis in line with the cutter.

The invention may be understood more readily, and various other features of the in-110 vention may become apparent, from consideration of the following description.

DRAWINGS

Figure 1 is an exploded isometric view of 11 5 the major elements of apparatus for finish cutting a die, parts being omitted;

Figure 2 is a plan view of the complete apparatus;

Figures 3 to 5 are sections on lines 3-3 to 120 5-5 of Fig. 2;

Figure 6 is a section on line 6-6 of Fig. 5;

Figures 7 and 8 are sections on lines 7-7 and 8-8 of Fig. 2;

Figure 9 is a section on line 9-9 of Fig. 2; 1 25 Figure W is an elevation viewed from plane 10-10 of Fig. 2;

Figure 11 is an enlarged section of a portion of Fig. 5;

Figure 12 is a section on line 12-12 of Fig. 130 11;

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Figure 73 is a plan view from plane 13-1 3 of Fig. 11; and

Figures 14 to 17 are diagrammatic plan views showing operation of the apparatus.

5

DESCRIPTION

1 — General Description — Figs. 1 to

10

11 — Positioning the Punch and Die — 10 Figs. 2 to 4

III — Cutter Blade—Figs. 3 and 10

IV — Template and Tracer — Figs. 2 to 4, 9 and 10

V — Cutting Straight Die Faces— Figs. 15 2 to 4, 6, 7 and 10

VI — Cutting Arcuate Die Faces — Figs.

2 to 6, 7, 8 and 11 to 1 7

I — General Description 20 In the illustrated example of the present invention the object is to make a finishing cut in the opening O of a female die workpiece W as shown in Fig. 2. It is customary to rough-cut the die opening to the interior outline 0 25 and then hand file the interior opening until it exactly matches the exterior outline of a male punch P shown to the left of the die W in Fig. 2. According to one aspect of the present invention the punch P is used as a template 30 for finish-cutting the die or workpiece W. The relation between the punch/template P and die/workpiece W is also shown clearly in Figs. 14 to 16.

Finish-cutting of the interior die opening 0 35 is done with a reciprocating saw blade S under control of a tracer T which follows the exterior outline of the punch/template P. The present apparatus turns the die/workpiece W so that the saw blade S is always at right 40 angles or normal to the interior face of the workpiece opening O. The saw blade strokes downwardly through the opening against the face then backing inwardly from the die face on the upward stroke, and by such strokes, 45 rapidly repeated as the die/workpiece W is move relatively to the blade under the control of the tracer T, cuts a smooth finish on the interior of the die exactly matching the exterior outline of the punch template P. 50 Fig 1. does not show the above described operating elements but does show the supports for those elements. The supports are a base 1 with pivots 101 for a tilting arm 2 with pivot plates 201 fitting between the base 55 pivots 101 through all of which a pivot pin passes. A screw 202 angularly adjusts the pivot arm relatively to the base. The tilting arm 2 has a secondary pivot plates 203 pivotaily pinned to pivot ears 303 found in 60 the sidewalls 301 of a base frame 3. The base frame 3 has a tab 304 with a linear slot 306 adapted to receive an eccentric pin as described under the caption VI — Cutting Arcuate Die Faces. The frame 3 also has two 65 guide rods 307 slidingly supporting a template carriage 4. The base 1, tilting arm 2 and base frame 3 are relatively adjustable but are motionless during die cutting operation.

The template carriage 4 supports the 70 punch/template P which, although not shown in Fig. 1, is carried on a bridge 401 with an aperture 405 having pivot pins 402 fitting in pivot plates 403. Below the template carriage are lugs 404 bored to fit on the guide rods 75 307 of the base frame below so that the template slides in a first direction 4* transversely of the base 1. The template carriage 4 also mounts a manual screw 408 for clamping the eccentric pin described under caption 80 VI. Upper guide rods 409 extend between tabs 411.

Above the template carriage 4 is a work-piece carriage 6 having inverted channels 601 fitting over the tabs 411 of the template 85 carriage. Inside the channels 601 are welded short tubes 602 sliding on the template upper guide rods 409 as best shown in Fig. 4. This sliding movement shown by the double headed arrow 6* is in a direction at right 90 angles to the motion 4* of the template carriage. A plate 604 with an opening 606 for the saw S is the base for a rotating workpiece holder 607 shown in Figs. 2 and 3. Standards 611 above the channels 601 support a 95 cross bar 608 for a cursor 102 which supports the tracer T following the outline of the punph/temp'ate P. A plate 609 below the workpiece carriage mounts rollers for a sprocket chain 104 connected between the 100 cursor and anchor 106 on the base frame.

II — Positioning the Punch and Die — Figs. 2 to 4

The punch, whose exterior outline serves as 105 a template for finish-cutting the die, is secured in a collar 412 which is rotatively journalled in the aperture 405 of the bridge 401 which in turn is pivotted by pins 402 on the template carriage 4. A base plate 413 is attached 110 by screws threaded into the punch/template P. The base plate 413 in turn is secured by a screw to a collar lining 414 fitting the punch P. Because of the adjustability of the work-piece the punch/template need not be pre-11 5 cisely positioned in the collar 41 2 so long as the upper face of the punch is normal to the axis of the collar and is free to be followed by the tracer.

The die/workpiece W with its rough-cut 120 opening 0 is loosely positioned by clamps

612 on the rotating work holder 607 with the opening 0 over the opening 606 for the saw S which is temporarily removed. Normally the work carriage 6 is positioned by the engage-125 ment of the saw S with the workpiece W as opposed by engagement of the tracer T with the punch/template P. When released the work carriage slides on the rods 409 to the phantom position W* shown in Fig. 3 in 1 30 which a tongue 613 under the carriage is

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received in the slot 413 of a boss 414 and secured by a set screw 416. The template bridge 401 is then released to swing on its pivot pins 402 by unfastening a latch 41 7 5 extending through a slot in a lug 418 adjacent one pivot 402 of the template bridge (Figs. 1 and 2). The bridge and punch-tem-plate are then free to swing 180° to a position where the punch is at the level of the work-10 piece and over the opening 0 in the work-piece W.

Prior to mounting in the cutting apparatus the punch has been used to indent a precise outline on the face of the die. Thereafter a 1 5 smaller opening inside the precisely intended outline has been rough-cut so that the precise indentation remains. The workpiece is now adjusted on its workholder until its indented outline is precisely aligned with the outline of 20 the punch/template and secured by clamps 612. The workpiece carriage tongue 613 is then released from its engagement in the slot 413 and, when released, the workpiece carriage slides on the rods 409 to the position 25 shown in solid lines in Fig. 3. Then the template bridge 401 is swung back to its solid line position in Figs. 2 and 3 and secured by the latch 417 in engagement with the tracer T.

30

III — Cutter Blade — Figs. 3 and 10

The saw cutter blade S is vertically reciprocated by a motor M on the base 1 linked by a belt 110 between pulleys 11 1 and 112. The 35 upper pulley 112, through an axle 115,

drives an eccentric 11 3 which reciprocates a sa\A/ plunger 114 under the constraint of a spring 116, the upper end of the plunger being connected axially to a lower saw blade 40 clamp 11 7. A standard 118 arising from the base 1 extends to a head 11 9 in which an upper plunger 121 reciprocates. The plunger 121 is suspended from a spring 125 and carries a pivoted lever 122 with a hook 123 45 which supports the upper end of the saw S. In its solid line position in Fig. 3 the lever 1 22 holds the saw vertical on its down stroke. The cutting edges of the saw teeth are then parallel to the interior outline of the die open-50 ing 0 and thus chisel or scrape a flat face, under the control of the punch template, from the rough-cut opening, up to the precise finish cut outline. Because many blade strokes are taken for short advances of the blade in the 55 order of a blade thickness along the opening a very polished finish cut can be achieved.

The teeth of the saw are angled downward for cutting on the downstroke, and when the saw completes its up stroke a set screw 1 20 60 strikes one end of the lever 1 22 swinging the saw blade S away from the workpiece momentarily.

As the saw S repeatedly moves to engage the workpiece during its down stroke and 65 swings at the end of its up stroke, the tracer T

advances to engage the punch/template P and retracts from engagement at the end of the saw up stroke while the saw is moving along the cut surface and the tracer T is 70 moving along the punch/template surface. The tracer T thus vibrates to and from engagement with the punch/template, this vibration allowing the tracer to skip sidewise over rough irregularities in the face of the 75 punch/template which might resist lateral movement of the tracer T along the punch/template P. In this way the vibrating motion of the blade aids smooth tracing of the template. The extent of blade vibration can be 80 adjusted by the set screw 120 to control the ease of tracing.

IV — Template and Tracer — Figs. 2 to 4, 8 to 10

85 It has been made clear that the punch P ultimately to be used with the die W which is finish-cut with the present apparatus, this punch, is also the template which is followed by a tracer T to control the finish cutting of 90 the die. While it is accurate to say that the tracer T follows the external outline of the punch/template P the tracer on its cursor 102 is held against transverse movement along the workpiece carriage crossbar 608 by a 95 sprocket chain 104. The punch/template P moves transversely of the tracer T, parallel to the crossbar 608 and transversely of the direction of cutting of the saw blade S. The tracer, however, does move with the work-100 piece carriage 6, at right angles to the crossbar 608, or longitudinally in the direction of cutting.

The sprocket chain 104 which anchors the cursor 1 02 to the base 1 against transverse 105 movement, as shown in Fig. 4, is guided from its anchor 106 on the base 1 in a closed loop over rollers on the workpiece carriage 6, 126, 127 and 128 leading to the cursor 102, and thence over rollers 129, 131 and 132 leading 110 back to the base anchor 106. The base anchor 106 is a rod secured to the tilting arm 2 on the base, the rod passing through an oversized link 105 in the chain 104. The oversized link 105 slides on the anchor rod 115 106 as the workpiece carriage 4* moves transversely of the base. The other chain anchor, best shown in Fig. 9, is a hook 132 attached underneath the tracer cursor 102 with a tip 133 extending through the sprocket 1 20 chain between its link pins.

The purpose of anchoring the tracer cursor 102 with the chain 104 is to allow the workpiece carriage 6, its standard 611 and crossbar 608 to support the cursor 102 slidin-1 25 gly so that the workpiece carriage 6 can move transversely of the base 1 without moving the cursor 102 and its tracer T transversely also. That is, the tracer is fixed relative to the base 1 against movement transversely of the saw 130 cutting direction as is the saw cutter, while

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the workpiece carriage 6 and punch/template carriage 4 are movable transversely.

As shown in Fig. 9 the tracer cursor 102 is slidingly supported on the workpiece crossbar 5 608 by a clamp 616 on a channel 615 under the cursor body. The tracer itself is a rod with a beveled end engaging the punch/template P and a threaded shank surrounded by a thumb screw 617 longitudinal adjustment of 10 the tracer rod. The cursor has a tongue which slides longitudinally in a socket 619 mounted on the channel 61 5. A micrometer 621 adjusts the longitudinal position of the cursor such that the tracer T engages the pun-1 5 ch/template P at a point corresponding to the cutting engagement of the saw blade S with the workpiec'e W.

As will be explained in more detail the engagement of the tracer T with the pun-20 ch/template P controls movement of the die/workpiece W in relation to the saw S.

V — Cutting Straight Die Faces — Figs. 2 to 4, 7 and 10 25 There are two manual drives, which of course could be motorized. One is for driving the punch/template carriage 4, and work-piece carriage thereon, linearly transversely of the base 1 and cutting direction of the saw 30 blade S. The second is for rotating the punch/template P on its carriage 4 and simultaneously rotating the die/workpiece W on its carriage 6.A third movement, longitudinally of the base 1 parallel to common or parallel 35 planes through the template is effected by interaction of the tracer T and punch/template P.

The first manual linear drive is effected by a first handcrank 311 rotating in a bearing 40 block 312 (Figs. 1, 2, 4 and 6). As shown in Fig. 6 the crank 311 has a pair of toothed jaws 313 engaging a threaded stud 418 staked in a bracket 419 depending from the workpiece table 4. A thumb screw 316 draws 45 the jaws into a sleeve 317 engaging the jaws with the thread on the stud 418. When released from the sleeve 31 7 by turning the thumb screw the jaws spring open out of engagement with the thread thus freeing the 50 template carriage 4 and allowing it to slide without restraint on the rods 307 if the base frame 3 for automatic movement described under caption VI — Cutting Arcuate Die Faces. The linear drive crank 311 is used for 55 moving the die/workpiece W and punch/template P when cutting straight on plane faces of the die.

Prior to beginning a straight cut a straight edge of the workpiece W and template P 60 must, be oriented transversely of the base. For example, in Fig. 2 the punch/template P has an arcuate surface opposite the tracer T; and the blade S is opposite a rounded interior surface of the workpiece. Both the template P 65 -and workpiece W must be rotated until straight faces of each are opposite the tracer T and saw blade S respectively. For this purpose the second rotary drive is used.

The origin of the rotary drive is a hand 70 wheel 421 on a bracket 422 arising from the template carriage 4. The bracket 422 journals a shaft 423 at whose end is a worm 424 meshing with worm wheel 426 on the collar 412 holding the punch/template P (Figs. 2, 75 3, 4, 7 and 10). Rotation of the handwheel 421 rotates the punch template and also drives two gear chains.

The first, rotary gear train linked to the hand wheel 421 drives the workpiece holder 80 607 and consists of a spur gear 427 on the shaft 423 and linking gears 428, 429 and 431 (Fig. 3). The last gear 431 is on a slip coupled shaft 432 at whose end is a worm 433 meshing with worm wheel 434 driving 85 the rotary work holder 607.

With this first rotary drive off the hand wheel 421 the collar holding the punch/template P and the die/workpiece W may be rotated counter to each other until one of the 90 linear faces of the workpiece is rotated from the position shown in Fig. 2 to a position in which the linear face is transverse the saw-blade S and a corresponding face of the die/template is transverse the tracer T, as 95 shown for example in Fig. 15.

The saw motor M can then be turned on and cutting of the linear face can be started by turning the linear drive hand screw 311. The tracer T will remain fixed as it traverses 100 the straight exterior face of the punch/template and the saw S cuts along the mirror image interior surface of the die/workpiece.

It is an important aspect of the present invention that because the saw blade S en-105 gages the workpiece W in the same direction as the tracer T engages the punch/template P the reaction of kickback of the workpiece resulting from the impact of the saw blade will in turn micrometrically urge the workpiece 110 W, its carriage 6 and the tracer T carried on the workpiece carriage crossbar 608 in a direction which urges the tracer T toward the punch/template P. This reaction is most simply shown in Fig. 15 wherein reaction of the 115 workpiece W and its holder 607 would tend to move the workpiece carriage 6 upwardly toward the top of Fig. 1 5. Such upward movement would press the tracer T on the workpiece carriage 6 into closer engagement 120 with the punch/template P. This mirror image reaction insures that the saw blade will be guided in its cut by close following of the tracer T along the punch/template P. Even if the template is not perfectly aligned at right 1 25 angles to a common plane through the tracer and saw, the saw will cut precisely the outline of the punch/template. That is, the interaction of the tracer T and template P would automatically adjust the workpiece carriage 6 1 30 longitudinally of the cutting plane so that the

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saw in effect would follow the punch/template surface.

VI — Cutting Arcuate Die Faces — Figs. 2 to 5 6, 7, 8 and 11 to 17

In addition to finish-cutting straight faces on a die or other workpiece it is often necessary to a fillet or like arcuate surface such as is shown engaged by the blade S in Fig. 2. An 10 arcuate surface could be cut by turning the rotary drive wheel 421 previously described. But the arc turned would necessarily have a radius determined by the distance between the curved surface and the central axis C of 1 5 rotation of the workholder 607, whereas the arc desired might have a much shorter radius on an axis offset from the axis C of rotation of the workholder 607. The present apparatus compensates for the offset of the workholder 20 axis and the workpiece surface axis.

As shown in Figs. 2 and 4 the collar 412 holding the punch/template P and turned by the rotary hand wheel 421 carries a ring gear 437 which engages another ring gear. The 25 second ring gear is normally coupled to a bevel gear 439 by a lock screw 441 which may be loosened to decouple the two gears. The bevel gear is the first in a gear train which includes a double bevel gear 442, a 30 single bevel gear 443 connected through a shaft 444 to a spur gear 446, all shown in Fig. 4. As shown in Figs. 2 and 5, the gear train further includes gears 447 and 448 connecting gear 446 to a gear 449 which 35 turns an off-axis compensating rotor 40 including the manual clamping screw 408, all ge£rs of this train being mounted on the template carriage 4. As shown in detail in Figs. 11 and 12 the compensating rotor 40 40 comprises a stem 451 into the upper end of which is threaded the clamping screw 408. The lower end of the stem extends through the gear 449 and is welded to a cross pin 452. A rider 453 having an eccentric pin 454 45 extending below it into the slot 306 in the tab 304 of the base frame 3 shown in Fig. 1. Tightening the clamp screw 408 draws the stem 451 cross pin 452 and rider 453 upward clamping the rider against the gear 449 50 so that the stem rider turns with the gear. Normally the clamp screw is loose and the stem, cross bar and eccentric pin are locked against rotation by a spring urged pin 456 retractable by a thumb screw 457. Moreover, 55 if the eccentric pin 454 is positioned coaxially with the rotor stem as shown in Figs. 11 and 12 its eccentricity is zero and rotation has no affect. In cutting an arcuate surface however, the eccentric pin is offset either to the right or 60 left of the coaxial position shown in Fig. 12. To prepare for arcuate cutting the release 316 for the linear handcrank 311 is loosened disconnecting the template and workpiece carriages 4 and 6 from the linear drive so that 65 they are free to move transversely of the cutting plane (3-3 in Fig. 14) subject to the control of the punch/template and the eccentric pin 454. The worktable is then rotated and moved transversely until the saw is on 70 and at the beginning of the arc to be cut. As shown in Fig. 15, this adjustment will offset the eccentric screw 454 from the center of the rotor 40 by the same amount as the center of the arc to be cut is offset from the 75 center C of rotation of the worktable 607. Then the clamp screw 408 is tightened to hold the pin in eccentric position, and further the lock screw 441 is tightened to couple the gear train between the template collar 412 80 and the rotor gear 449.

The arcuate surface is then finish-cut by actuating the saw and turning the rotary drive hand wheel so that the template and work-piece are rotated mirror image-wise through 85 the position shown in Fig. 1 6 to the end of the arcuate cut shown in Fig. 17. Note that as the cut progresses rotation of the eccentric pin in the slot 306 of the tab fixed, motionless on the base frame 3 causes the template and 90 workpiece carriages 4 and 6 to move leftward enough to compensate for the initial offset, or difference between the radius of the work-piece rotation and of the arcuate surface. Thus in Figs. 1 6 and 1 7 the two carriages 4 and 6 95 have moved transversely to the left of their positions in Fig. 1 5. Longitudinal movement also seen in Figs. 1 5 to 17 is controlled by the engagement of the template P by the tracer T. The result is that, as shown, a 100 circular arc of 180° is smoothly finish-cut with both ends tangent to the adjacent straight portions.

To revert to straight cutting (Fig. 14) the rotor clamp screw releases the eccentric pin, 105 the rotor gear train is uncoupled by loosening the screw 441 and the screw 31 6 is tightened to re-engage the linear drive crank 311.

It should be understood that the present disclosure is for the purpose of illustration 110 only and that this invention includes all modifications and equivalents which fall within the scope of the appended claims.

Claims

115 1. Apparatus for cutting a predetermined outline on a workpiece; said apparatus comprising a base, a workpiece carriage and a template carriage movably mounted one upon the other and upon the base, a cutter on the 120 base, a workpiece holder on the workpiece carriage for holding the workpiece for movement with the workpiece carriage relative to the cutter, a template on the template carriage having the predetermined outline, and a tracer 125 on the workpiece carriage for following the template outline, the cutter and tracer respectively engaging the workpiece and template in the same direction so that reaction of the workpiece to cutting action urges the template 130 and tracer into engagement.

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2. Apparatus according to claim 1 wherein the carriages mechanically link the workpiece and template for simultaneouse movement in mirror image relation.

5 3. Apparatus according to claim 1 or 2 wherein the tracer engages an exterior template outline and the cutter engages an interior workpiece outline.

4. Apparatus according to claim 1. 2 or 3 10 wherein the tracer and cutter are at fixed positions transversely of the cutting direction and the template and workpiece carriages move the template and workpiece relative to the fixed positions.

15 5. Apparatus according to any one of claims 1 to 4 and further including means slidingly supporting one carriage on the other carriage for movement in a first direction.

6. Apparatus according to claim 5 includ-20 ing means slidingly supporting the other carriage on the base for movement in a second direction.

7. Apparatus according to claim 6 wherein the first and second directions are in the

25 direction of cutting and are at right angles thereto.

8. Apparatus according to claims 1, 3 or 6 wherein the tracer and cutter lie in common or parallel planes and the carriages respec-

30 tively move in directions parallel and normal to said planes.

9. Apparatus according to claim 1 and further including means for driving said one carriage in a first direction.

35 10. Apparatus according to claim 9

wherein interaction of the template and tracer to driving one carriage in the first direction urges the template and both carriages in a second direction.

40 11. Apparatus according to claim 1 and further including a template holder rotatably mounted on the template carriage, the work-piece holder securing the workpiece for rotation about a first axis, a rotary drive coupling 45 the template holder and workpiece holder for coordinated rotation of the template and work-piece while cutting an arcuate outline around a second axis, and an eccentric coupled to said drive for moving the workpiece carriage 50 to hold the second axis in line with the cutter.

12. Apparatus according to claim 11, wherein the eccentric rotates on one of the carriages.

1 3. Apparatus according to claim 1 2 55 wherein the eccentric engages the base.

14. Apparatus according to claim 11 or 1 2 wherein the eccentricity compensates for the spdomn of the second axis from the work-piece £iXI3

60 15 Apparatus according to any one of claims 11 to 1 4 wherein the eccentric is adjustable.

16 Apparatus according to claim 1 5 wherein the eccentric comprises a rotor on the 65 template carriage coupled to the rotary drive.

a diametric guide on the rotor, an eccentric member sliding on the guide between a position on the axis of the rotor and adjusted positions eccentric thereof, means for holding 70 the pin in adjusted position, and a slot on the base receiving the pin, whereby rotary motion of the workpiece rotary drive moves the template carriage in a direction to compensate for the aforesaid axis spacing. 75 17. Apparatus according to claim 1

wherein the template and workpiece carriages hold the template and workpiece at different levels, the template carriage including a template holder pivotted on the template carriage 80 so that the template may be swung from the tracer to the level of the workpiece for axial alignment therewith.

18. Apparatus according to claim 1 7 wherein the template holder pivots 180 de-

85 grees in swinging from the tracer to the workpiece so as to reverse its outline.

19. Apparatus according to claims 1 to

1 7 wherein the workpiece comprises an unfinished metal forming die having an aperture 90 within an interior outline and the template comprises a punch with the same exterior outline.

20. Apparatus according to claim 1 including means on the workpiece carriage to

95 mount the tracer fixed in a direction transverse of the cutting direction and movable in the direction of cutting.

21. Apparatus according to claim 20 wherein the tracer mount includes a track on

100 the workpiece carriage slidingly engaging the tracer the workpiece carriage being movable longitudinally of the cutting direction.

22. Apparatus according to claim 21 including means linking the tracer to the base

105 to hold the tracer fixed in the direction transverse of the cutting direction.

23. Apparatus according to claim 22 wherein the linking means comprises an endless belt-like linkage, means on the workpiece

110 carriage guiding the linkage on a path between a connection to the tracer and an anchor on the base.

24. Apparatus according to claim 23 wherein said anchor comprises a sliding con-

115 nection between the linkage and the base allowing movement of the linkage with the workpiece carriage.

25. Apparatus according to claim 1 including means to vibrate the cutter to and

1 20 from the workpiece.

26. Apparatus according to claim 25 including means to adjust the extent of cutter vibration.

27. Apparatus according to claim 25

125 wherein the carriages constitute a linkage between the saw and tracer causing the tracer to vibrate to and from the template thereby to facilitate tracing along the template.

28. Apparatus according to claim 25 or

1 30 27 wherein the cutter constitutes a reciprocal

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ing saw and the means to vibrate comprises means to move the saw to and from the workpiece on the saw strokes.

29. Apparatus for cutting a predetermined 5 outline on a female die workpiece; said apparatus comprising a base, a first carriage, movably mounted on the base, a second carriage movably mounted on the first carriage, cutting means supported by the base, for engagement 10 with a workpiece mounted to the second carriage, a template mounted on the first carriage and defining said predetermined outline and a follower or finger mounted on the second carriage for engaging and following 1 5 the template to control the cutting means whereby during cutting the follower and the cutting means are maintained in engagement with the template and the workpiece respectively.

20 30. Apparatus substantially as described with reference to, and as illustrated in, the accompanying drawings.

Printed for Her Majesty's Stationery Office by Burgess & Son (Abingdon) Ltd.—1981.

Published at The Patent Office, 25 Southampton Buildings,

London, WC2A 1AY, from which copies may be obtained.